Apologies. Wrong link for the DIP version, corrected version In terms of memory upgrades you will need a specific M100 RAM module. I believe Francesco Messineo, who is also on this group, builds and sells modules for the M100. I could not find his email contact address at the moment.
If you feel like building your own I have two different styles of an M100 memory module PCB on OSH Park that you can order and build. One PCB is for a Surface Mount module (https://oshpark.com/shared_projects/Ra3VwoJo) and the other for a DIP version (https://oshpark.com/shared_projects/V0tpeuMg) of the same design.
